I want to connect my cable box to my tv but have absolutely no clue. The tv is older so I don’t have any instructions, and the internet isn’t helping. They all say to hit the antenna button on the menu, or the cable button, but those buttons are not there. I have the cable box connected to the tv through the ANT/CABLE thing on he back with a coaxial cable but have absolutely no clue how I can watch the **bleep** cable box.
Depending on your TV model, look on the TV remote (not Roku or cable remote) for a button that says "input" or "source" and press it. You can look for a similar button on the TV itself.
Once you select the Antenna (or whatever label your coaxial connection is called), then you can switch to the cable remote to turn channels.
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This is actually a Roku support forum you wandered into, so not sure if you have a RokuTV or just an older standard TV.
Adding to @AvsGunnar's reply ...
Most cable boxes that output via coax cable can be set to output on channels 3 or 4. Set your tv to view whichever channel was set on the cable box, then use the cable remote to control which cable channel you view (in standard definition, as that's all a coax connection can support).